SAN LEANDRO — A San Leandro High School teacher is facing criminal charges after authorities found child pornography on a school computer.

The investigation began after the teacher mistakenly showed students a nude photograph of himself, authorities said Monday.

Richard Styner, 45, of San Leandro, has been charged with possession of child pornography and first-degree residential burglary, according to the Alameda County District Attorney’s Office.

Authorities say Styner was teaching a computer class at the high school on April 16 when he allegedly displayed a naked picture of himself on a video screen during a class presentation on how to transfer pictures from electronic devices. His students range in age from 14 to 18.

Styner reported the incident to the school’s administration, who called police, San Leandro police Lt. Randall Brandt said. A subsequent search of a school computer found photographs and more than 200 pornographic stories, court documents show. In one story, a 14-year-old girl has sex with her brother, according to court papers, and it includes a photograph of a nude female who appears to be under the age of 18.

Styner is facing a first-degree residential burglary charge for entering a friend’s home while she was out of town in October 2012, according to a probable cause statement filed with the court. Styner had a key for emergency purposes.

Authorities say he set out the woman’s underwear, running pants and other items from her dresser and photographed them. He also allegedly had altered photographs of the woman’s face on naked bodies, records show.

San Leandro Unified School District Superintendent Cindy Cathey said in a statement that Styner has been placed on unpaid administrative leave. The district is cooperating with police and prosecutors and is conducting its own investigation, Cathey said.

Styner, who was not taken into custody, has been sent a notice to appear in Alameda County Superior Court for arraignment next week and has cooperated with police, Brandt said. Styner could not be reached for comment Monday.

Police are encouraging residents who may have information about the allegations to report them to police.

David DeBolt is a senior breaking news reporter for the San Jose Mercury News and the East Bay Times of Oakland. Over the past decade, DeBolt has covered the deadly San Bruno PG&E pipeline explosion, police and government corruption, California wildfires and Oakland City Hall. He was part of the East Bay Times staff honored with the 2017 Pulitzer Prize for coverage of the Ghost Ship warehouse fire.